Rotary pump



Au 11, 1953 J.- P. JOHNSON ROTARY PUMP 1 WW w WM m w m im M P 6 MM AX lALLY GROOVED 42 SURFACES AXIALLY GROOVED SURFACES 'iled Jan. 18, 1950Aug. 11, 1953 J. P. JOHNSON I 2,648,289

ROTARY PUMP iled Jan. 18, 1950 I 2 Sheets-Sheet 2 IN VEN TOR.

06% riwAV/L Patented Aug. 11, 1953 UNITED STATES PATENT OFFICE ROTARYPUMP James P. Johnson, Shaker Heights, Ohio Application January 18,1950, Serial No. 139,261

13 Claims.

1, The present invention relates generally as indicated to rotary pumpsand more particularly to rotary pumps of the character which includepump members interconnected generally in the manner of an Oldhamcoupling or in other words a sliding coupling for parallel shafts.

It is one primary object of this invention to provide rotary pumps whichmay be operated at high speeds and low temperatures because of theelimination to a great degree of high-speed sliding or rubbing contactsbetween the displacement chamber forming elements thereof.

As a further object of this invention, also imputed to the aforesaidelimination of highspeed rubbing contacts, is the capability ofv the useof the present pumps with fluids such as air or other fluids which donot have lubricating properties whereas 'in the common forms of gear,sliding vane, screw, and like pumps of the positive displacement type,the friction between sliding surfaces is considerable thus restrictingthe use of the last-mentioned type of pumps to use with oil or otherliquids which have lubricating properties. Moreover, pumps of thelast-mentioned type require the maintenance of extremely close fitsbetween the rubbing surfaces in order to achieve a reasonable volumetricefficiency thereby further restricting the use of these pumps to usewith fluids which have sufficient viscosity to prevent excessiveleakage.

Therefore, another object of this invention is to provide rotary pumpswhich are so formed that the opposed and relatively moving surfaces ofthe displacement chamber forming elements need not be extremely closelyfitted, that is, sizable clearances may be maintained withoutcorrespondingloss of volumetric efliciency.

, Another object of this invention is to provide rotary pumps in whichthe bearing loads are at least semi-balanced.

Another object of this invention is to provide rotary pumps in which theperipheral wall of the pump casing chamber is of unique shape and simpleto form as compared with the usual walls of vane pumps which includegenerally elliptical,

limacon, Archimedes spiral, or other special sections which aredifficult to generate.

Other objects and advantages will'become apparent as the followingdescription proceeds.

To the accomplishmentof the foregoing and related ends, said invention,then, comprises the features hereinafter fully described andparticularly pointed out in the claims, the following description andthe annexed drawingsetting forth in detail certain illustrativeembodimentsof'the invention, these being indicative, however, of

except showing the pump assembly in a different rotative position; and

Fig. 5 is a cross-section view similar to Fig. 1 illustrating amodification.

Referring now more specifically to the drawing and first to Fig. 1,there is shown therein a pump casing part I of generally tubular formprovided with a cylindrical bore 2 formed with axially spaced undercuts3 and 4 from which lead the passages 5 and 6 to the respective ports Iand 8 in said casing part.

Secured to said casing'part I as by bolts or other suitable means (notshown) is a casing part or head 9 which defines with said casing part Ia cylindrical chamber comprising the bore 2 and opposed parallel endwalls I0 and II.

a sleeve I4 and annular liners or plates I5 and It at opposite endsthereof, said sleeve and plates preferably being made of graphite, forexample, or if desired from any other material having requiredproperties.

As best shown in Figs. 3 and 4, said sleeve I4 is formed with a pair ofdiametrically opposed openings I! through the wall thereof whichregister with one of the undercuts 3il and with another pair ofdiametrically opposed openings I8 through the wall thereof whichregister with the other of said undercuts 3-4. Said openings arecircumierentially spaced to provide relatively narrow barriers I9therebetween.

The bore through said sleeve I4 is of an oblong form consisting of apair of cylindrical sections 20 and 2Ihaving parallel axes 22 and 23respectively and intersecting along the lines 24 in barriers I9. Thewall of such sleeve bore is preferably formed with a large number offine grooves or serrations from one end to the other to provide, as willhereinafter more specifically be pointed out, a series of dams orchannels which are operative to effectively resist leakage of fluidtherepast even though appreciable clearance is provided between the ribsof said grooves or serrations and the ribs of the correspondinglyserrated or grooved outer surface of the pump assembly now to bedescribed. The term fine grooves or serrations as herein used indicatesgrooves of .001 to .010 inch depth for example and spaced apart a likedistance to provide ribs of corresponding width and height, and the termappreciable clearance likewise covers a range from about .001 to .010inch.

Journalled in the pump casing as on bearings 25 for rotation about axis23 is a shaft 26 which has secured at one end thereof as by the pin 21 apump member 28. Said pump member 28 is in the form of a cross-headincluding a hub 29 in which the ends of said pin 21 are anchored, andradially extending arms 30 terminating in diametrically opposed segments3| of diameter corresponding generally with the diameter of thecylindrical section 2| of the sleeve bore. The outer cylindricalsurfaces of said segments 3| are also preferably formed with a series offine grooves or serrations which operate in the manner previouslyindicated to eliminate flow of fluid between the segments 3| and thecylindrical section 2| of said sleeve bore. By so scarfing the pumpmember 28 and sleeve M the clearance space between the peaks or ribs ofthe scarfed surfaces may be spaced apart several thousandths of an inchas indicated whereas pumps usually require the maintenance of a veryclose clearance, usually less than one-thousandth of an inch. Saidsegments 3| extend from one liner plate l to the other liner plate l6and have a running fit therebetween.

Also journalled in said pump casing as on bearings 32 is another shaft33 which may be integrally formed with a cross-head constituting anotherpump member 34, said pump member comprising arms 35 terminating indiametrically opposed segments 36 of the same form as the segments 3|previously described. The outer cylindrical surfaces of said segments 36are again preferably scarfed or serrated and the end faces of saidsegments 36 again having a running fit between said liner plates I5 andI6. Said shaft 33 rotates about the axis 22 and likewise the segments 36have outer cylindrical surfaces which are coaxial with the cylindricalsection of the bore sleeve I4 and of diameter generally correspondingwith the diameter of section 20 and preferably slightly less aspermitted by the scarfing of the opposed surfaces.

Between the aforesaid pump members or crossheads 28 and 34 is a couplingblock 31 which, as best shown in Fig. 2 is of rectangular cross-sectionor more properly of square cross-section in a plane normal to the axesof the pump members and has a bore 38 therethrough and is formed with aslot 39 thereacross which permits fitting of the block over the hub 29and arms of pump member 28 while further permitting transverse movementof said block with respect to the axis of said pump member. The opposedparallel faces 43 of said block have a relatively close sliding fitwithin corresponding parallel chordal faces 4| of segments 3|.

Said block is also formed with another slot 42 thereacross disposed atright angles to the slot 39, said slot 42 having a loose fit over thearms 35 and hub of pump member 34 and the opposed faces 43 of said blockhave a sliding fit between the chordal faces 44 of the segments 36whereby said block may partake of transverse sliding with respect topump member 34 along a path at right angles to the path of relativetransverse sliding of said block with respect to said pump member 28.

In the embodiment of the invention illustrated in Fig. 1, the shaft 33extends through casing part 9 and constitutes the drive shaft of thepump. However, it will be apparent that, if desired, the other shaft 26could be extended through cover plate I2 to constitute the drive shaftof the pump.

As best shown in Fig. 3, pump members 28 and 34 and coupling block 31constitute a pump assembly dividing the chamber in the pump casing intoa plurality of independent spaces which as evident from a comparison ofFigs. 3 and 4 alternately increase and decrease in size and alternatelycommunicate with the openings H and I8 in sleeve |4 during rotation ofthe pump assembly whereby to effect intake and discharge of fluid fromthe respective ports 1 and 8. When the pump assembly is rotated in thedirection indicated by arrow 45, the openings |1 constitute intakeopenings and the openings |B constitute discharge openings and obviouslythe direction of rotation may be reversed to correspondingly reverse thepump.

The aforesaid spaces are formed between adjacent segments 3| and 36which seal with the bore in sleeve I4 and end walls of plates l5 and Hiand coupling block 31 which seals with the chordal faces 4| and 44 ofadjacent segments. It is preferred that block 31 be of a size such thatin the position of the parts as shown in Fig. 4, a corner thereof willbe in relatively close proximity to the line of intersection 24 of thecylindrical sections 20 and 2| in the bore of sleeve |4 so as tominimize leakage between openings l1 and I8 at one barrier I9 andsimilarly it is preferred that the segments 3| and 36 be ofcircumferential extent so as to substantially abut each other as theypass the intersection 24 as shown in the lower portion of Fig. 4 so asto minimize the leakage between openings I1 and I8 at the other barrierl9.

Referring again to Figs. 3 and 4, rotation of the pump assembly whichcomprises said pump members 28 and 34 and said coupling block 31 in thedirection indicated by the arrow 45 in Fig. 3 will cause progressiveenlargement of the space 46 while in communication with one opening |1whereas the space 41 has just increased to maximum size and has been cutoff from the other opening H by the edge of the upper segment 36 and isready to decrease in size and to be brought into communication with thelower opening [8 by the uncovering of the latter opening by the edge ofthe lower segment 36. At this instant the space 48 is decreasing in sizewhile in communication with the upper opening l8.

Referring now to Fig. 4, the pump assembly has been rotated 45 in aclockwise direction from Fig. 3 to illustrate how the spaces vary insize. In this case, the space 46 is still increasing in size while incommunication with lower opening H, such increase continuing during thenext 45 rotation until said space 46 is of size the same as space 41 inFig. 3 and cut off from openings l1 and I8 by the edges of segments 3|.During the rotation of the pump assembly from Fig. 3 to Fig. 4, thespace 41 decreases in size while in communication with the lower opening|8 and the space 48vhas decreased to minimum size and has been cut offfrom upper opening l8 by the edge of segment 3|. Upon further rotationof the pump assembly from Fig; 4, said space 48 will increase in sizeand will'be in communication with upper opening |1.

As now evident, the pump assembly divides the chamber in the pump easinginto a plurality of spaces which alternately increase and decrease insize and alternately communicate with paired openings leading into thechamber to effect intake and discharge of fluid, said spaces beingdefined by a portion of the wall of section 2!) or 2| extending from aline of intersection 24 to the edge of a segment 3| or 36 and by theouter surface of a segment eccentric withrespect to the section or 2| inquestion, the corner of the coupling block 31, and the edge of thefirst-mentioned segment. Of course, in some positions of the pumpassembly the spaces are defined by the edges of one pair of segments 3|or 36, a portion of the wall of section 2|] or 2| between such segments,the outer surface of a segment eccentric to the section in question, andtwo corners of coupling block 31, as for example the space 41 in Fig. 3.

It is further to be noted that by reason of the disposition of theopenings l1 and I8 in sleeve I4, as shown, the load on the bearings and32 is semi-balanced.

The form of the invention illustrated in Fig. 5 is generally the same asthat just described except that a shaft is non-rotatably fixed as bymeans of a pin 5| in the pump casing part 52 and projects through oneofthe liner plates 53 into the chamber defined between the sleeve 54 andliner plates 53 and 55. ing, end of said shaft 50 is a bushing 56 ofdesired bearing material and rotatable on said bushing is a pump member51 of the form substantially the same as pump member '28 in Fig. 2.

Another shaft 58 is rotatable in a similar bushing 59 about an axisparallel to the axis of shaft 50, said shaft extending through a coverplate 60 secured as by bolts 6| to pump casing part 52 to thusconstitute the drive shaft. Here again the drive shaft 58 is formed witha pump member 62 in the form of a crooss-head substane tially asshown atthe right-hand side of Fig. 2. 4

pling is a coupling block 63 of form similar to block 31 as illustratedin the middle of Fig. 2, said pump members 51 and 62 beingof diametercorresponding to the diameters of intersecting cylindrical wall sectionsin sleeve 54 having parallel axes.

' Insofar as the basic principle of operation-is the same as for thepump illustrated in Figs. 1-4, the operation of the Fig. 4 modificationneed not be repeated. As before, the pump casing part 52 is formed withports 64 and 65 each of which has a passage 66 and 61 respectivelyleading to the undercuts 68 and 69 formed in casing bore 10, saidundercuts 68 and 69 communicating with respective pairs of diametricallyopposed openings formed through the wall of sleeve 54. As apparent tothose skilled in the art, the porting of the pump may be arranged in anynumber of different ways too numerous to illustrate and describe. Itwill further be understood by those skilled in the art that the pumpchamber in which the pump members 28, 34, and 51, 52 are disposed mayconstitute opposed axially On such project-' spaced walls of. the pumpcasing parts with thespecial form of peripheral. wall of the pumpchamber formed directly in a pump casing part rather than in a sleeveinserted therein. However, as before indicated, it is preferred. to formthe pump chamber from sleeves and end liner as regards the detailsdescribed, provided the;

features stated in any of the following claims, or the equivalent ofsuch be employed.

I therefore particularly point out and distinctly claim as my invention:

1. A rotary pump comprising a casing pro-- vided with a chamber andfluid inlet and discharge ports leading int such chamber, and a pumpassembly rotatable within such chamber and dividing such chamber into aplurality of spaces which alternately increase and decrease in size andalternately communicate with such ports during rotation of saidassembly, the peripheral wall of such chamber including intersectingsections of circular transverse crosssection struck from spaced andparallel axes, and said assembly comprising intersecting members mountedin said casing for rotation about axes respectively coinciding with theaxes of the aforesaid sections of theperipheral wall of such chamber andof diameter substantially the same as the'respective sections, and acoupling block having a non-rotatable and transversely slidableconnection with said members and forming therewith and with such chambersuch plurality of spaces, and drive means for rotating said as-- semblyin said casing.

2. A rotary pump comprising acasing formed with a chamber which includesparallel end walls and an oblong peripheral wall consisting of twointersecting sections of circular transverse-crosssection struck fromspaced and parallel axes and with fluid inlet and discharge portsleading into such chamber, and a pump assembly rotatable within suchchamber and dividing the same into a plurality of spaces whichalternately increase anddecrease in size and alternately communicatewith such ports during rotation of said assembly, said assemblycomprising intersecting members mounted in said casing for rotationabout axes respectively coinciding with the axes of the aforesaidsections of the peripheral wall of such chamber and of diametersubstantially the same as the respective sections, and a coupling blockhaving a non-rotatable and transversely slidable connection with saidmembers and forming therewith and with such chamber such plurality of'spaces, anddrive means for rotating said assembly in said casing.

3. A rotary pump comprising a casing formed with a chamber whichincludes parallel end walls and an oblong peripheral wall consisting oftwo intersecting sections of circular transverse crosssection struckfrom spaced and parallel axes and with fluid inlet and discharge portsleading into such chamber, and a pump assembly rotatable withinsuchchamber and dividing the same into a plurality of spaces whichalternately increase and decrease in size and alternately communicatewith such ports during rotation ofsaid assembly, said assemblycomprising intersecting members mounted in said casing for rotationabout axes respectively coinciding with the axes of the aforesaidsections of the peripheral wall of such chamber and of diametersubstantially the same as the respective sections, and a coupling blockhaving a non-rotatable and transversely slidable connection with saidmembers and forming therewith and with such chamber such plurality ofspaces, and drive means for rotating said assembly in said casing, eachof said members comprising a cross head formed with diametricallyopposed segmental sections extending from one end wall to the other ofsuch chamber, and said coupling block being of rectangular cross-sectionwith opposite faces transversely slidably fitted within the segmentalsections of the respective members.

4. A rotary pump comprising a casing formed with a chamber whichincludes parallel end walls and an oblong peripheral wall consisting oftwo intersecting sections of circular transverse crosssection struckfrom spaced and parallel axes and with fluid inlet and discharge portsleading into such chamber, and a pump assembly rotatable within suchchamber and dividing the same into a plurality of spaces whichalternately increase and decrease in size and alternately communicatewith such ports during rotation of said assembly, said assemblycomprising intersecting members mounted in said casing for rotationabout axes respectively coinciding with the axes of the aforesaidsections of the peripheral wall of such chamber and of diametersubstantially the same as the respective sections, and a coupling blockhaving a non-rotatable and transversely slidable connection with saidmembers and forming therewith and with such chamber such plurality ofspaces, and drive means for rotating said assembly in said casing, eachof said members comprising a cross head formed with diametricallyopposed segmental sections extending from one end wall to the other ofsuch chamber, and said coupling block being of rectangular cross-sectionwith opposite faces transversely slidably fitted within the segmentalsections of the respective members, said coupling block being of suchsize that the corners thereof pass in close proximity to the lines ofintersection of the aforesaid sections of such chamber during rotationof said pump assembly.

5. A rotary pump comprising a casing formed with a chamber whichincludes parallel end walls and an oblong peripheral wall consisting oftwo intersecting sections of circular transverse cross-section struckfrom spaced and parallel axes and with fluid inlet and discharge portsleading into such chamber, and a pump assembly rotatable within suchchamber and dividing the same into a plurality of spaces whichalternately increase and decrease in size and alternately communicatewith such ports during rotation of said assembly, said assemblycomprising intersecting members mounted in said casing for rotationabout axes respectively coinciding with the axes of the aforesaidsections of the peripheral wall of such chamber and of diametersubstantially the same as the respective sections, and a coupling blockhaving a nonrotatable and transversely slidable connection with saidmembers and forming therewith and with such chamber such plurality ofspaces, and drive means for rotating said assembly in said casing, eachof said members comprising a cross head formed with diametricallyopposed segmental sections extending from one end wall to the other ofsuch chamber, and said coupling block being of rectangular cross-sectionwith opposite faces transversely slidably fitted within the segmentalsections of the respective members, the segmental sections extendingcircumferentially t a degree such that the edges of adjacent sectionsperiodically substantially abut at the lines of intersection of theaforesaid sections of such chamber during rotation of said pumpassembly.

6. A rotary pump comprising a casing provided with a chamber and fluidinlet and discharge ports leading into such chamber, and a pump assemblyrotatable within such chamber and dividing such chamber into a pluralityof spaces which alternately increase and decrease in size andalternately communicate with such ports during rotation of saidassembly, the peripheral wall of such chamber and the opposed surfacesof said pump assembly which define such spaces being formed with aseries of grooves extending generally lengthwise of the axis of rotationof said pump assembly whereby appreciable clearance may be providedwithout corresponding leakage of fluid between such spaces and betweensuch ports.

'7. A rotary pump comprising a casing formed with a cylindrical chambertherein having parallel end walls and with fluid intake and dischargeports leading to such chamber, a sleeve in such chamber formed with twopairs of diametrically opposed openings through the wall thereofrespectively in communication with such ports, the respective openingsof one pair being circumferentially spaced from the openings of theother pair, said sleeve being formed with an oblong bore therethroughconsisting of two parallel cylindrical sections which intersect alongtwo lines respectively disposed between one of the openings of each pairof openings and the other of the openings of each pair of openings, apair of intersecting vane-like members journalled in said casing forrotation about axes coinciding with the axes of the respectivecylindrical sections of such sleeve bore, said members each includingopposite segmental sections of diameter substantially the same as therespective cylindrical section and extending from one end wall to theother of such chamber, a coupling block of rectangular cross sectionhaving its two pairs of opposed faces transversely slidably fittedwithin the segmental sections of the respective members, said membersand coupling constituting a pump assembly and defining with such sleevebore a plurality of independent spaces which alternately increase anddecrease in size and alternately communicate with such openingsresponsive to rotation of said assembly, and a drive shaft connectedcoaxially to one of said members and extending exteriorly of said casingwhereby said pump assembly may be rotated.

8. A rotary pump comprising a casing formed with a cylindrical chambertherein having parallel end walls and with fluid intake and dischargeports leading to such chamber, a sleeve in such chamber formed with twopairs of diametrically opposed openings through the wall thereofrespectively in communication with such ports, the respective openingsof one pair being circumferentially spaced from the openings of theother pair, said sleeve being formed with an oblong bore therethroughconsisting of two parallel cylindrical sections which intersect alongtwo lines respectively disposed between one of the openings of each pairof openings and the other of the openings of each pair of openings, apair tr m of intersecting vane-like members journalled' in said casingfor rotation about axes coinciding with the axes of the respectivecylindrical sections of such sleeve bore, said members each includingopposite segmental sections of diameter substantially the same as therespective cylindrical section and extending from one end wall to theother of such chamber, a coupling block of rectangular cross-sectionhaving its two pairs of opposed faces transversely slidably fittedwithinthe segmental sections of the respective members, said members andcoupling constituting a pump assembly and defining with such sleeveborea plurality of independent spaces which alternately increase anddecrease in size and alternately communicate with such openingsresponsive to rotation of said assembly, and a drive shaft connectedcoaxially to one of said members and extending exteriorly of said casingwhereby said pump assembly may be rotated, said segmental sections ofeach member being of suflicient circumferential extent to precludecommunication between successive openings in said sleeve.

9. A rotary pump comprising a casing formed with a cylindrical chambertherein having parallel ends walls and with fluid intake and dischargeports leading to such chamber, a sleeve in such chamber formed with twopairs of diametrically opposed openings through the wall thereofrespectively in communication with such ports, the respective openingsof one pair being circumferentially spaced from the openings of theother pair, said sleeve being formed with an oblong bore therethroughconsisting of two parallel cylindrical sections which intersect alongtwo lines respectively disposed between one of the openings of each pairof openings and the other of the openings of each pair of openings, apair ofintersecting vane-like members journalled in said casing forrotation about axes coinciding with the axes of the respectivecylindrical sections of such sleeve bore, said members each includingopposite segmental sections of diameter substan tially the same as therespective cylindrical section and extending from one end wall to theother of such chamber, a coupling block of rectangular cross-sectionhaving its two pairs of opposed faces transversely slidably fittedwithin the segmental sections of the respective members, said membersand coupling constituting a pump assembly and defining with such sleevebore a plurality of independent spaces which alternately increase anddecrease in size and alternately communicate with such openingsresponsive to rotation of said assembly, and a drive shaft connectedcoaxially to one of said members and extending exteriorly of said casingwhereby said pump assembly may be rotated, said segmental sections ofeach member being of sufiicient circumferential extent so that the edgesof adjacent sections substantially abut each other as they pass thelines of intersection of such cylindrical sections of such sleeve borewhereby to preclude communication between the openings on opposite sidesof the lines of intersection.

10. A rotary pump comprising a casing formed with a cylindrical chambertherein having paral lel end walls and with fluid intake and dischargeports leading to such chamber, a sleeve in such chamber formed with twopairs of diametrically opposed openings through the wall thereofrespectively in communication with such ports, the respective openingsof one pair being circumferentially spaced from the openings of theother pair, said sleeve being formed with an oblong bore therethroughconsisting of two parallel bers journalled in said casing for rotationabout axes coinciding with the axes of the respective cylindricalsections of such sleeve bore, said members each including oppositesegmental sections of diameter substantially the same asthe respectivecylindrical section and extending from'one end wallito' the other ofsuchchamber, a coupling block of rectangular cross-section having its twopairs of opposed faces transversely slidably fitted within the segmentalsections of the respective members, said members and couplingconstituting a pump assembly and defining with such sleeve bore aplurality of independent spaces which alternately increase and decreasein size and alternately communicate with such openings responsive torotation of said assembly, and a drive shaft connected coaxially to oneof said members and extending exteriorly 'tif said casing whereby saidpump assembly-n'iiiif be rotated, said coupling block being of size'such that in certain positions of the pump assembly a corner of saidblock is in close proximity to one of the lines of intersection of suchsleeve bore whereby to preclude communication between the openings onopposite sides of such line of intersection.

11. A rotarypump comprising a casing formed with a cylindrical chambertherein having parallel end walls and with fluid intake and dischargeports leading to suchchamber, a sleeve in such chamber formed with twopairs of diametrically opposed openings through the wall thereofrespectively in communication with such ports, the-respective openingsof one pair being circumferentially spaced from the openings of theother pair, said sleeve being formed with an oblong bore therethroughconsisting of tWo parallel cylindrical sections which intersect alon twolines respectively disposed between one of the openings of each pair ofopenings and the other of the openings of each pair of openings, a pairof intersecting vane-likemembers journalled in said casing for rotationabout axes coinciding with the axes of the respective cy lindricalsections of such sleeve bore, said members each including oppositesegmental sections of diameter substantially the same as the respectivecylindrical section and extending from one end wall to the other of suchchamber, a coupling block of rectangular cross-section having its twopairs of opposed faces transversely slidably fitted within the segmentalsections of the respective members, said members and couplingconstituting a pump assembly and defining with such sleeve bore aplurality of independent spaces which alternately increase and decreasein size and alternately communicate with such openings responsive torotation of said assembly, and a drive shaft connected coaxially to oneof said members and extending exteriorly of said casing whereby saidpump assembly may be rotated, the surface of such sleeve bore and the,outer cylindrical surfaces of said members being formed with a seriesof grooves extending from one end to the other whereby appreciableclearance may be provided without corresponding leakage between suchspaces and openings.

12. A rotary pump comprising a casing formed with a cylindrical chambertherein having parallel end walls and with fluid intake and dischargeports leading to such chamber, a sleeve in such chamber formed with twopairs of d ametrically opposed openings through the wall thereofrespectively in communication with such ports, the respective openingsof one pair being circumferentially spaced from the openings of theother pair, said sleeve being formed with an oblong bore therethroughconsisting of two p allel cylindrical sections which intersect alon twolines respectively disposed between one of the openings of each pair ofopenings and the other of the openings of each pair of openings, a pairof intersecting vane-like members journalled in said casing for rotationabout axes coinciding with the axes of the respective cylindricalsections of such sleeve bore, said members each including oppositesegmental sections of diameter substantially the same as the respectivecylindrical section and extending from one end wall to the other of suchchamber, a coupling block of rectangular cross-section having its twopairs of opposed faces transversely slidably fitted within t l esegmental sections of the respective meni bersgsaid members and couplingconstituting a puinp assembly and defining with such sleeve bore aplurality of independent spaces which alternately increase and decreasein size and alternately communicate with such openings responsive torotation of said assembly, and a drive shaft connected coaxially to oneof said members and extending exteriorly of said casing whereby saidpump assembly may be rotated, the surface of such Sleeve bore and theouter cylindrical surfaces of said members being formed with a series ofgrooves extending from one end to the other whereby appreciableclearance may be provided without corresponding leakage between suchspaces and opening such grooves preferably being .001 to .010 inch deepand a corresponding distance apart to define ribs therebetween wherebythe clearance between the ribs in such bore and the ribs on said membersmay vary from .001 to .010 inch but yet without permitting excessiveleakage between such spaces and openings during rotation of said pumpassembly and without generating excessive frictional heat.

13. A rotary pump comprising a casing formed with a cylindrical chambertherein having parallel end walls and with fluid intake and dischargeports leading to such chamber, a sleeve 12 in such chamber formed withtwo pairs of diametrically opposed openings through the wall thereofrespectively in communication with such ports, the respective openingsof one pair being circumferentially spaced from the openings of theother pair, said sleeve being formed with an oblong bore therethroughconsisting of two parallel cylindrical sections which intersect alon twolines respectively disposed between one of the openings of each pair ofopenings and the other of the openings of each pair of openings, a pairof intersecting vane-like members journalled in said casing for rotationabout axes coinciding with the axes of the respective cylindricalsections of such sleeve bore, said members each including oppositesegmental sections of diameter substantially the same as the respectivecylindrical section and extending from one end wall to the other of suchchamber, a coupling block of rectangular cross-section having its twopairs of opposed faces transversely slidably fitted within the segmentalsections of the respective members, said members and couplingconstituting a pump assembly and defining with such sleeve bore aplurality of independent spaces which alternately increase and decreasein size and alternately communicate with such openings responsive torotation of said assembly, and a drive shaft connected coaxially to oneof said members and extending exteriorly of said casing whereby saidpump assembly may be rotated, and liner plates in said casing disposedat the opposite ends of said sleeve and constituting the parallel endwalls of such chamber, said sleeve and liners being made of bearingmaterial.

JAMES P. JOHNSON.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,729,764 Dinesen Oct. 1, 1929 2,079,375 McCollum May 4, 19372,273,034 Grey Feb. 17, 194 2,399,990 Culver May 7, 1946 2,503,257Graham Apr. 11, 1950 FOREIGN PATENTS Number Country Date 203,291 GreatBritain 1924

